1. Field of the Invention
This invention relates to a method of operating a common elevator. More particularly, the present invention pertains to an elevator operating method in which the mode can be changed over during the operation of the elevator so as to change the type of floors to which the elevator is serviced.
2. Description of the Related Art
The usage of the conventional common elevator, disclosed in Japanese Patent Laid-Open No. 1-231793, will be described below with reference to FIG. 3. An office building 7 and a residential building 8 are attached. A common elevator 6 is installed on the adjoining portion between the two buildings. Normally, the major time period in which the elevator 6 is used in the office building 7 differs from that in which the elevator 6 is used in the residential building 8. Therefore, the period of non-use of the common elevator 6 can be reduced, and the operation efficiency of the elevator 6 can thus be increased.
In recent years, composite buildings 1 have been built in urban areas to enhance the land use efficiency. Such a composite building 1 ma contain office floors 3 which occupy the lower portion of the building 1 and residential floors 2 occupying the upper portion thereof, as shown in FIG. 4. In the composite building 1, elevator service is offered for both the floors 3 and 2 using a common elevator 4 which travels to all floors, including the office floors 3 and the residential floors 2.
However, the common elevator 4 may violate the privacy of the residents who live on the residential floors 2 and permit violation of the security of the office floors 3. Hence, in a case where provision of the privacy of the residents on the residential floors 2 and of the security of the office floors 3 is required, common elevators are not installed but elevators are installed and operated separately for the individual residential floors and office floors.
However, the provision of separate elevators for residential and office floors in a composite building increases installation costs and space. Furthermore, since the time periods in which the elevators exclusively used for the residential floors is used generally differ from the time that the elevators exclusively used for the office floors is used. Therefore, the frequency with which the elevators are used is reduced, thus reducing operational efficiency thereof, which is uneconomical.